Bug fix: trying to register new user on locked AnObj crash

-> now raise a PermissionDenied

-> for a TTP shared, accept registration

adim_project/adim/permissions.py

@@ -34,9 +34,10 @@ class PermissionClass(object):
         raise NotImplementedError()
 
     def _register_user(self, user, anobj):
-        if not anobj.locked:
-            AnObjMembership.objects.create(anobj=anobj, user=user)
-            # anobj.members.add(user)
+        if anobj.locked:
+            return False
+        AnObjMembership.objects.create(anobj=anobj, user=user)
+        return True
 
     def _revoke_user(self, user, anobj):
         if not anobj.locked:
@@ -164,6 +165,10 @@ class ATTP(PermissionClass):
     def __init__(self, ttp_id=None):
         self.ttp_id = ttp_id
 
+    def _register_user(self, user, anobj):
+        AnObjMembership.objects.create(anobj=anobj, user=user)
+        return True
+
     def set_attp_status(self, request, anobj, status):
         key = "attp_{ttp_id}{user_id}{uuid}".format(
             ttp_id=self.ttp_id, user_id=request.user.id,
@@ -209,7 +214,8 @@ class ATTP(PermissionClass):
 
         else:
             if request.user not in anobj.members.all():
-                self._register_user(request.user, anobj)
+                if not self._register_user(request.user, anobj):
+                    raise PermissionDenied()
 
             # Check ownership
             owners = anobj.owners.all()